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<div class="subTitle">org.apache.commons.math3.stat.descriptive.moment</div>
<h2 title="Class Variance" class="title">Class Variance</h2>
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<li><a href="../../../../../../../org/apache/commons/math3/stat/descriptive/AbstractUnivariateStatistic.html" title="class in org.apache.commons.math3.stat.descriptive">org.apache.commons.math3.stat.descriptive.AbstractUnivariateStatistic</a></li>
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<dd><a href="http://docs.oracle.com/javase/7/docs/api/java/io/Serializable.html?is-external=true" title="class or interface in java.io">Serializable</a>, <a href="../../../../../../../org/apache/commons/math3/stat/descriptive/StorelessUnivariateStatistic.html" title="interface in org.apache.commons.math3.stat.descriptive">StorelessUnivariateStatistic</a>, <a href="../../../../../../../org/apache/commons/math3/stat/descriptive/UnivariateStatistic.html" title="interface in org.apache.commons.math3.stat.descriptive">UnivariateStatistic</a>, <a href="../../../../../../../org/apache/commons/math3/stat/descriptive/WeightedEvaluation.html" title="interface in org.apache.commons.math3.stat.descriptive">WeightedEvaluation</a>, <a href="../../../../../../../org/apache/commons/math3/util/MathArrays.Function.html" title="interface in org.apache.commons.math3.util">MathArrays.Function</a></dd>
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<pre>public class <span class="strong">Variance</span>
extends <a href="../../../../../../../org/apache/commons/math3/stat/descriptive/AbstractStorelessUnivariateStatistic.html" title="class in org.apache.commons.math3.stat.descriptive">AbstractStorelessUnivariateStatistic</a>
implements <a href="http://docs.oracle.com/javase/7/docs/api/java/io/Serializable.html?is-external=true" title="class or interface in java.io">Serializable</a>, <a href="../../../../../../../org/apache/commons/math3/stat/descriptive/WeightedEvaluation.html" title="interface in org.apache.commons.math3.stat.descriptive">WeightedEvaluation</a></pre>
<div class="block">Computes the variance of the available values.  By default, the unbiased
 "sample variance" definitional formula is used:
 <p>
 variance = sum((x_i - mean)^2) / (n - 1) </p>
 <p>
 where mean is the <a href="../../../../../../../org/apache/commons/math3/stat/descriptive/moment/Mean.html" title="class in org.apache.commons.math3.stat.descriptive.moment"><code>Mean</code></a> and <code>n</code> is the number
 of sample observations.</p>
 <p>
 The definitional formula does not have good numerical properties, so
 this implementation does not compute the statistic using the definitional
 formula. <ul>
 <li> The <code>getResult</code> method computes the variance using
 updating formulas based on West's algorithm, as described in
 <a href="http://doi.acm.org/10.1145/359146.359152"> Chan, T. F. and
 J. G. Lewis 1979, <i>Communications of the ACM</i>,
 vol. 22 no. 9, pp. 526-531.</a></li>
 <li> The <code>evaluate</code> methods leverage the fact that they have the
 full array of values in memory to execute a two-pass algorithm.
 Specifically, these methods use the "corrected two-pass algorithm" from
 Chan, Golub, Levesque, <i>Algorithms for Computing the Sample Variance</i>,
 American Statistician, vol. 37, no. 3 (1983) pp. 242-247.</li></ul>
 Note that adding values using <code>increment</code> or
 <code>incrementAll</code> and then executing <code>getResult</code> will
 sometimes give a different, less accurate, result than executing
 <code>evaluate</code> with the full array of values. The former approach
 should only be used when the full array of values is not available.</p>
 <p>
 The "population variance"  ( sum((x_i - mean)^2) / n ) can also
 be computed using this statistic.  The <code>isBiasCorrected</code>
 property determines whether the "population" or "sample" value is
 returned by the <code>evaluate</code> and <code>getResult</code> methods.
 To compute population variances, set this property to <code>false.</code>
 </p>
 <p>
 <strong>Note that this implementation is not synchronized.</strong> If
 multiple threads access an instance of this class concurrently, and at least
 one of the threads invokes the <code>increment()</code> or
 <code>clear()</code> method, it must be synchronized externally.</p></div>
<dl><dt><span class="strong">See Also:</span></dt><dd><a href="../../../../../../../serialized-form.html#org.apache.commons.math3.stat.descriptive.moment.Variance">Serialized Form</a></dd></dl>
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<h3>Field Summary</h3>
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<caption><span>Fields</span><span class="tabEnd">&nbsp;</span></caption>
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<th class="colFirst" scope="col">Modifier and Type</th>
<th class="colLast" scope="col">Field and Description</th>
</tr>
<tr class="altColor">
<td class="colFirst"><code>protected boolean</code></td>
<td class="colLast"><code><strong><a href="../../../../../../../org/apache/commons/math3/stat/descriptive/moment/Variance.html#incMoment">incMoment</a></strong></code>
<div class="block">Whether or not <a href="../../../../../../../org/apache/commons/math3/stat/descriptive/moment/Variance.html#increment(double)"><code>increment(double)</code></a> should increment
 the internal second moment.</div>
</td>
</tr>
<tr class="rowColor">
<td class="colFirst"><code>protected <a href="../../../../../../../org/apache/commons/math3/stat/descriptive/moment/SecondMoment.html" title="class in org.apache.commons.math3.stat.descriptive.moment">SecondMoment</a></code></td>
<td class="colLast"><code><strong><a href="../../../../../../../org/apache/commons/math3/stat/descriptive/moment/Variance.html#moment">moment</a></strong></code>
<div class="block">SecondMoment is used in incremental calculation of Variance</div>
</td>
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<h3>Constructor Summary</h3>
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<caption><span>Constructors</span><span class="tabEnd">&nbsp;</span></caption>
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<th class="colOne" scope="col">Constructor and Description</th>
</tr>
<tr class="altColor">
<td class="colOne"><code><strong><a href="../../../../../../../org/apache/commons/math3/stat/descriptive/moment/Variance.html#Variance()">Variance</a></strong>()</code>
<div class="block">Constructs a Variance with default (true) <code>isBiasCorrected</code>
 property.</div>
</td>
</tr>
<tr class="rowColor">
<td class="colOne"><code><strong><a href="../../../../../../../org/apache/commons/math3/stat/descriptive/moment/Variance.html#Variance(boolean)">Variance</a></strong>(boolean&nbsp;isBiasCorrected)</code>
<div class="block">Constructs a Variance with the specified <code>isBiasCorrected</code>
 property</div>
</td>
</tr>
<tr class="altColor">
<td class="colOne"><code><strong><a href="../../../../../../../org/apache/commons/math3/stat/descriptive/moment/Variance.html#Variance(boolean,%20org.apache.commons.math3.stat.descriptive.moment.SecondMoment)">Variance</a></strong>(boolean&nbsp;isBiasCorrected,
        <a href="../../../../../../../org/apache/commons/math3/stat/descriptive/moment/SecondMoment.html" title="class in org.apache.commons.math3.stat.descriptive.moment">SecondMoment</a>&nbsp;m2)</code>
<div class="block">Constructs a Variance with the specified <code>isBiasCorrected</code>
 property and the supplied external second moment.</div>
</td>
</tr>
<tr class="rowColor">
<td class="colOne"><code><strong><a href="../../../../../../../org/apache/commons/math3/stat/descriptive/moment/Variance.html#Variance(org.apache.commons.math3.stat.descriptive.moment.SecondMoment)">Variance</a></strong>(<a href="../../../../../../../org/apache/commons/math3/stat/descriptive/moment/SecondMoment.html" title="class in org.apache.commons.math3.stat.descriptive.moment">SecondMoment</a>&nbsp;m2)</code>
<div class="block">Constructs a Variance based on an external second moment.</div>
</td>
</tr>
<tr class="altColor">
<td class="colOne"><code><strong><a href="../../../../../../../org/apache/commons/math3/stat/descriptive/moment/Variance.html#Variance(org.apache.commons.math3.stat.descriptive.moment.Variance)">Variance</a></strong>(<a href="../../../../../../../org/apache/commons/math3/stat/descriptive/moment/Variance.html" title="class in org.apache.commons.math3.stat.descriptive.moment">Variance</a>&nbsp;original)</code>
<div class="block">Copy constructor, creates a new <code>Variance</code> identical
 to the <code>original</code></div>
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<h3>Method Summary</h3>
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<caption><span>Methods</span><span class="tabEnd">&nbsp;</span></caption>
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<th class="colFirst" scope="col">Modifier and Type</th>
<th class="colLast" scope="col">Method and Description</th>
</tr>
<tr class="altColor">
<td class="colFirst"><code>void</code></td>
<td class="colLast"><code><strong><a href="../../../../../../../org/apache/commons/math3/stat/descriptive/moment/Variance.html#clear()">clear</a></strong>()</code>
<div class="block">Clears the internal state of the Statistic</div>
</td>
</tr>
<tr class="rowColor">
<td class="colFirst"><code><a href="../../../../../../../org/apache/commons/math3/stat/descriptive/moment/Variance.html" title="class in org.apache.commons.math3.stat.descriptive.moment">Variance</a></code></td>
<td class="colLast"><code><strong><a href="../../../../../../../org/apache/commons/math3/stat/descriptive/moment/Variance.html#copy()">copy</a></strong>()</code>
<div class="block">Returns a copy of the statistic with the same internal state.</div>
</td>
</tr>
<tr class="altColor">
<td class="colFirst"><code>static void</code></td>
<td class="colLast"><code><strong><a href="../../../../../../../org/apache/commons/math3/stat/descriptive/moment/Variance.html#copy(org.apache.commons.math3.stat.descriptive.moment.Variance,%20org.apache.commons.math3.stat.descriptive.moment.Variance)">copy</a></strong>(<a href="../../../../../../../org/apache/commons/math3/stat/descriptive/moment/Variance.html" title="class in org.apache.commons.math3.stat.descriptive.moment">Variance</a>&nbsp;source,
    <a href="../../../../../../../org/apache/commons/math3/stat/descriptive/moment/Variance.html" title="class in org.apache.commons.math3.stat.descriptive.moment">Variance</a>&nbsp;dest)</code>
<div class="block">Copies source to dest.</div>
</td>
</tr>
<tr class="rowColor">
<td class="colFirst"><code>double</code></td>
<td class="colLast"><code><strong><a href="../../../../../../../org/apache/commons/math3/stat/descriptive/moment/Variance.html#evaluate(double[])">evaluate</a></strong>(double[]&nbsp;values)</code>
<div class="block">Returns the variance of the entries in the input array, or
 <code>Double.NaN</code> if the array is empty.</div>
</td>
</tr>
<tr class="altColor">
<td class="colFirst"><code>double</code></td>
<td class="colLast"><code><strong><a href="../../../../../../../org/apache/commons/math3/stat/descriptive/moment/Variance.html#evaluate(double[],%20double)">evaluate</a></strong>(double[]&nbsp;values,
        double&nbsp;mean)</code>
<div class="block">Returns the variance of the entries in the input array, using the
 precomputed mean value.</div>
</td>
</tr>
<tr class="rowColor">
<td class="colFirst"><code>double</code></td>
<td class="colLast"><code><strong><a href="../../../../../../../org/apache/commons/math3/stat/descriptive/moment/Variance.html#evaluate(double[],%20double[])">evaluate</a></strong>(double[]&nbsp;values,
        double[]&nbsp;weights)</code>
<div class="block">
 Returns the weighted variance of the entries in the the input array.</div>
</td>
</tr>
<tr class="altColor">
<td class="colFirst"><code>double</code></td>
<td class="colLast"><code><strong><a href="../../../../../../../org/apache/commons/math3/stat/descriptive/moment/Variance.html#evaluate(double[],%20double[],%20double)">evaluate</a></strong>(double[]&nbsp;values,
        double[]&nbsp;weights,
        double&nbsp;mean)</code>
<div class="block">Returns the weighted variance of the values in the input array, using
 the precomputed weighted mean value.</div>
</td>
</tr>
<tr class="rowColor">
<td class="colFirst"><code>double</code></td>
<td class="colLast"><code><strong><a href="../../../../../../../org/apache/commons/math3/stat/descriptive/moment/Variance.html#evaluate(double[],%20double[],%20double,%20int,%20int)">evaluate</a></strong>(double[]&nbsp;values,
        double[]&nbsp;weights,
        double&nbsp;mean,
        int&nbsp;begin,
        int&nbsp;length)</code>
<div class="block">Returns the weighted variance of the entries in the specified portion of
 the input array, using the precomputed weighted mean value.</div>
</td>
</tr>
<tr class="altColor">
<td class="colFirst"><code>double</code></td>
<td class="colLast"><code><strong><a href="../../../../../../../org/apache/commons/math3/stat/descriptive/moment/Variance.html#evaluate(double[],%20double[],%20int,%20int)">evaluate</a></strong>(double[]&nbsp;values,
        double[]&nbsp;weights,
        int&nbsp;begin,
        int&nbsp;length)</code>
<div class="block">Returns the weighted variance of the entries in the specified portion of
 the input array, or <code>Double.NaN</code> if the designated subarray
 is empty.</div>
</td>
</tr>
<tr class="rowColor">
<td class="colFirst"><code>double</code></td>
<td class="colLast"><code><strong><a href="../../../../../../../org/apache/commons/math3/stat/descriptive/moment/Variance.html#evaluate(double[],%20double,%20int,%20int)">evaluate</a></strong>(double[]&nbsp;values,
        double&nbsp;mean,
        int&nbsp;begin,
        int&nbsp;length)</code>
<div class="block">Returns the variance of the entries in the specified portion of
 the input array, using the precomputed mean value.</div>
</td>
</tr>
<tr class="altColor">
<td class="colFirst"><code>double</code></td>
<td class="colLast"><code><strong><a href="../../../../../../../org/apache/commons/math3/stat/descriptive/moment/Variance.html#evaluate(double[],%20int,%20int)">evaluate</a></strong>(double[]&nbsp;values,
        int&nbsp;begin,
        int&nbsp;length)</code>
<div class="block">Returns the variance of the entries in the specified portion of
 the input array, or <code>Double.NaN</code> if the designated subarray
 is empty.</div>
</td>
</tr>
<tr class="rowColor">
<td class="colFirst"><code>long</code></td>
<td class="colLast"><code><strong><a href="../../../../../../../org/apache/commons/math3/stat/descriptive/moment/Variance.html#getN()">getN</a></strong>()</code>
<div class="block">Returns the number of values that have been added.</div>
</td>
</tr>
<tr class="altColor">
<td class="colFirst"><code>double</code></td>
<td class="colLast"><code><strong><a href="../../../../../../../org/apache/commons/math3/stat/descriptive/moment/Variance.html#getResult()">getResult</a></strong>()</code>
<div class="block">Returns the current value of the Statistic.</div>
</td>
</tr>
<tr class="rowColor">
<td class="colFirst"><code>void</code></td>
<td class="colLast"><code><strong><a href="../../../../../../../org/apache/commons/math3/stat/descriptive/moment/Variance.html#increment(double)">increment</a></strong>(double&nbsp;d)</code>
<div class="block">Updates the internal state of the statistic to reflect the addition of the new value.</div>
</td>
</tr>
<tr class="altColor">
<td class="colFirst"><code>boolean</code></td>
<td class="colLast"><code><strong><a href="../../../../../../../org/apache/commons/math3/stat/descriptive/moment/Variance.html#isBiasCorrected()">isBiasCorrected</a></strong>()</code>&nbsp;</td>
</tr>
<tr class="rowColor">
<td class="colFirst"><code>void</code></td>
<td class="colLast"><code><strong><a href="../../../../../../../org/apache/commons/math3/stat/descriptive/moment/Variance.html#setBiasCorrected(boolean)">setBiasCorrected</a></strong>(boolean&nbsp;biasCorrected)</code>&nbsp;</td>
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<code><a href="../../../../../../../org/apache/commons/math3/stat/descriptive/AbstractStorelessUnivariateStatistic.html#equals(java.lang.Object)">equals</a>, <a href="../../../../../../../org/apache/commons/math3/stat/descriptive/AbstractStorelessUnivariateStatistic.html#hashCode()">hashCode</a>, <a href="../../../../../../../org/apache/commons/math3/stat/descriptive/AbstractStorelessUnivariateStatistic.html#incrementAll(double[])">incrementAll</a>, <a href="../../../../../../../org/apache/commons/math3/stat/descriptive/AbstractStorelessUnivariateStatistic.html#incrementAll(double[],%20int,%20int)">incrementAll</a></code></li>
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<h3>Methods inherited from class&nbsp;org.apache.commons.math3.stat.descriptive.<a href="../../../../../../../org/apache/commons/math3/stat/descriptive/AbstractUnivariateStatistic.html" title="class in org.apache.commons.math3.stat.descriptive">AbstractUnivariateStatistic</a></h3>
<code><a href="../../../../../../../org/apache/commons/math3/stat/descriptive/AbstractUnivariateStatistic.html#evaluate()">evaluate</a>, <a href="../../../../../../../org/apache/commons/math3/stat/descriptive/AbstractUnivariateStatistic.html#getData()">getData</a>, <a href="../../../../../../../org/apache/commons/math3/stat/descriptive/AbstractUnivariateStatistic.html#getDataRef()">getDataRef</a>, <a href="../../../../../../../org/apache/commons/math3/stat/descriptive/AbstractUnivariateStatistic.html#setData(double[])">setData</a>, <a href="../../../../../../../org/apache/commons/math3/stat/descriptive/AbstractUnivariateStatistic.html#setData(double[],%20int,%20int)">setData</a>, <a href="../../../../../../../org/apache/commons/math3/stat/descriptive/AbstractUnivariateStatistic.html#test(double[],%20double[],%20int,%20int)">test</a>, <a href="../../../../../../../org/apache/commons/math3/stat/descriptive/AbstractUnivariateStatistic.html#test(double[],%20double[],%20int,%20int,%20boolean)">test</a>, <a href="../../../../../../../org/apache/commons/math3/stat/descriptive/AbstractUnivariateStatistic.html#test(double[],%20int,%20int)">test</a>, <a href="../../../../../../../org/apache/commons/math3/stat/descriptive/AbstractUnivariateStatistic.html#test(double[],%20int,%20int,%20boolean)">test</a></code></li>
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<h3>Methods inherited from class&nbsp;java.lang.<a href="http://docs.oracle.com/javase/7/docs/api/java/lang/Object.html?is-external=true" title="class or interface in java.lang">Object</a></h3>
<code><a href="http://docs.oracle.com/javase/7/docs/api/java/lang/Object.html?is-external=true#clone()" title="class or interface in java.lang">clone</a>, <a href="http://docs.oracle.com/javase/7/docs/api/java/lang/Object.html?is-external=true#finalize()" title="class or interface in java.lang">finalize</a>, <a href="http://docs.oracle.com/javase/7/docs/api/java/lang/Object.html?is-external=true#getClass()" title="class or interface in java.lang">getClass</a>, <a href="http://docs.oracle.com/javase/7/docs/api/java/lang/Object.html?is-external=true#notify()" title="class or interface in java.lang">notify</a>, <a href="http://docs.oracle.com/javase/7/docs/api/java/lang/Object.html?is-external=true#notifyAll()" title="class or interface in java.lang">notifyAll</a>, <a href="http://docs.oracle.com/javase/7/docs/api/java/lang/Object.html?is-external=true#toString()" title="class or interface in java.lang">toString</a>, <a href="http://docs.oracle.com/javase/7/docs/api/java/lang/Object.html?is-external=true#wait()" title="class or interface in java.lang">wait</a>, <a href="http://docs.oracle.com/javase/7/docs/api/java/lang/Object.html?is-external=true#wait(long)" title="class or interface in java.lang">wait</a>, <a href="http://docs.oracle.com/javase/7/docs/api/java/lang/Object.html?is-external=true#wait(long,%20int)" title="class or interface in java.lang">wait</a></code></li>
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<h3>Field Detail</h3>
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<h4>moment</h4>
<pre>protected&nbsp;<a href="../../../../../../../org/apache/commons/math3/stat/descriptive/moment/SecondMoment.html" title="class in org.apache.commons.math3.stat.descriptive.moment">SecondMoment</a> moment</pre>
<div class="block">SecondMoment is used in incremental calculation of Variance</div>
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<pre>protected&nbsp;boolean incMoment</pre>
<div class="block">Whether or not <a href="../../../../../../../org/apache/commons/math3/stat/descriptive/moment/Variance.html#increment(double)"><code>increment(double)</code></a> should increment
 the internal second moment. When a Variance is constructed with an
 external SecondMoment as a constructor parameter, this property is
 set to false and increments must be applied to the second moment
 directly.</div>
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<pre>public&nbsp;Variance()</pre>
<div class="block">Constructs a Variance with default (true) <code>isBiasCorrected</code>
 property.</div>
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<pre>public&nbsp;Variance(<a href="../../../../../../../org/apache/commons/math3/stat/descriptive/moment/SecondMoment.html" title="class in org.apache.commons.math3.stat.descriptive.moment">SecondMoment</a>&nbsp;m2)</pre>
<div class="block">Constructs a Variance based on an external second moment.
 When this constructor is used, the statistic may only be
 incremented via the moment, i.e., <a href="../../../../../../../org/apache/commons/math3/stat/descriptive/moment/Variance.html#increment(double)"><code>increment(double)</code></a>
 does nothing; whereas <code>m2.increment(value)</code> increments
 both <code>m2</code> and the Variance instance constructed from it.</div>
<dl><dt><span class="strong">Parameters:</span></dt><dd><code>m2</code> - the SecondMoment (Third or Fourth moments work
 here as well.)</dd></dl>
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<pre>public&nbsp;Variance(boolean&nbsp;isBiasCorrected)</pre>
<div class="block">Constructs a Variance with the specified <code>isBiasCorrected</code>
 property</div>
<dl><dt><span class="strong">Parameters:</span></dt><dd><code>isBiasCorrected</code> - setting for bias correction - true means
 bias will be corrected and is equivalent to using the argumentless
 constructor</dd></dl>
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<pre>public&nbsp;Variance(boolean&nbsp;isBiasCorrected,
        <a href="../../../../../../../org/apache/commons/math3/stat/descriptive/moment/SecondMoment.html" title="class in org.apache.commons.math3.stat.descriptive.moment">SecondMoment</a>&nbsp;m2)</pre>
<div class="block">Constructs a Variance with the specified <code>isBiasCorrected</code>
 property and the supplied external second moment.</div>
<dl><dt><span class="strong">Parameters:</span></dt><dd><code>isBiasCorrected</code> - setting for bias correction - true means
 bias will be corrected</dd><dd><code>m2</code> - the SecondMoment (Third or Fourth moments work
 here as well.)</dd></dl>
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<pre>public&nbsp;Variance(<a href="../../../../../../../org/apache/commons/math3/stat/descriptive/moment/Variance.html" title="class in org.apache.commons.math3.stat.descriptive.moment">Variance</a>&nbsp;original)
         throws <a href="../../../../../../../org/apache/commons/math3/exception/NullArgumentException.html" title="class in org.apache.commons.math3.exception">NullArgumentException</a></pre>
<div class="block">Copy constructor, creates a new <code>Variance</code> identical
 to the <code>original</code></div>
<dl><dt><span class="strong">Parameters:</span></dt><dd><code>original</code> - the <code>Variance</code> instance to copy</dd>
<dt><span class="strong">Throws:</span></dt>
<dd><code><a href="../../../../../../../org/apache/commons/math3/exception/NullArgumentException.html" title="class in org.apache.commons.math3.exception">NullArgumentException</a></code> - if original is null</dd></dl>
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<pre>public&nbsp;void&nbsp;increment(double&nbsp;d)</pre>
<div class="block">Updates the internal state of the statistic to reflect the addition of the new value.
 <p>If all values are available, it is more accurate to use
 <a href="../../../../../../../org/apache/commons/math3/stat/descriptive/moment/Variance.html#evaluate(double[])"><code>evaluate(double[])</code></a> rather than adding values one at a time
 using this method and then executing <a href="../../../../../../../org/apache/commons/math3/stat/descriptive/moment/Variance.html#getResult()"><code>getResult()</code></a>, since
 <code>evaluate</code> leverages the fact that is has the full
 list of values together to execute a two-pass algorithm.
 See <a href="../../../../../../../org/apache/commons/math3/stat/descriptive/moment/Variance.html" title="class in org.apache.commons.math3.stat.descriptive.moment"><code>Variance</code></a>.</p>

 <p>Note also that when <a href="../../../../../../../org/apache/commons/math3/stat/descriptive/moment/Variance.html#Variance(org.apache.commons.math3.stat.descriptive.moment.SecondMoment)"><code>Variance(SecondMoment)</code></a> is used to
 create a Variance, this method does nothing. In that case, the
 SecondMoment should be incremented directly.</p></div>
<dl>
<dt><strong>Specified by:</strong></dt>
<dd><code><a href="../../../../../../../org/apache/commons/math3/stat/descriptive/StorelessUnivariateStatistic.html#increment(double)">increment</a></code>&nbsp;in interface&nbsp;<code><a href="../../../../../../../org/apache/commons/math3/stat/descriptive/StorelessUnivariateStatistic.html" title="interface in org.apache.commons.math3.stat.descriptive">StorelessUnivariateStatistic</a></code></dd>
<dt><strong>Specified by:</strong></dt>
<dd><code><a href="../../../../../../../org/apache/commons/math3/stat/descriptive/AbstractStorelessUnivariateStatistic.html#increment(double)">increment</a></code>&nbsp;in class&nbsp;<code><a href="../../../../../../../org/apache/commons/math3/stat/descriptive/AbstractStorelessUnivariateStatistic.html" title="class in org.apache.commons.math3.stat.descriptive">AbstractStorelessUnivariateStatistic</a></code></dd>
<dt><span class="strong">Parameters:</span></dt><dd><code>d</code> - the new value.</dd></dl>
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<pre>public&nbsp;double&nbsp;getResult()</pre>
<div class="block">Returns the current value of the Statistic.</div>
<dl>
<dt><strong>Specified by:</strong></dt>
<dd><code><a href="../../../../../../../org/apache/commons/math3/stat/descriptive/StorelessUnivariateStatistic.html#getResult()">getResult</a></code>&nbsp;in interface&nbsp;<code><a href="../../../../../../../org/apache/commons/math3/stat/descriptive/StorelessUnivariateStatistic.html" title="interface in org.apache.commons.math3.stat.descriptive">StorelessUnivariateStatistic</a></code></dd>
<dt><strong>Specified by:</strong></dt>
<dd><code><a href="../../../../../../../org/apache/commons/math3/stat/descriptive/AbstractStorelessUnivariateStatistic.html#getResult()">getResult</a></code>&nbsp;in class&nbsp;<code><a href="../../../../../../../org/apache/commons/math3/stat/descriptive/AbstractStorelessUnivariateStatistic.html" title="class in org.apache.commons.math3.stat.descriptive">AbstractStorelessUnivariateStatistic</a></code></dd>
<dt><span class="strong">Returns:</span></dt><dd>value of the statistic, <code>Double.NaN</code> if it
 has been cleared or just instantiated.</dd></dl>
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<pre>public&nbsp;long&nbsp;getN()</pre>
<div class="block">Returns the number of values that have been added.</div>
<dl>
<dt><strong>Specified by:</strong></dt>
<dd><code><a href="../../../../../../../org/apache/commons/math3/stat/descriptive/StorelessUnivariateStatistic.html#getN()">getN</a></code>&nbsp;in interface&nbsp;<code><a href="../../../../../../../org/apache/commons/math3/stat/descriptive/StorelessUnivariateStatistic.html" title="interface in org.apache.commons.math3.stat.descriptive">StorelessUnivariateStatistic</a></code></dd>
<dt><span class="strong">Returns:</span></dt><dd>the number of values.</dd></dl>
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<h4>clear</h4>
<pre>public&nbsp;void&nbsp;clear()</pre>
<div class="block">Clears the internal state of the Statistic</div>
<dl>
<dt><strong>Specified by:</strong></dt>
<dd><code><a href="../../../../../../../org/apache/commons/math3/stat/descriptive/StorelessUnivariateStatistic.html#clear()">clear</a></code>&nbsp;in interface&nbsp;<code><a href="../../../../../../../org/apache/commons/math3/stat/descriptive/StorelessUnivariateStatistic.html" title="interface in org.apache.commons.math3.stat.descriptive">StorelessUnivariateStatistic</a></code></dd>
<dt><strong>Specified by:</strong></dt>
<dd><code><a href="../../../../../../../org/apache/commons/math3/stat/descriptive/AbstractStorelessUnivariateStatistic.html#clear()">clear</a></code>&nbsp;in class&nbsp;<code><a href="../../../../../../../org/apache/commons/math3/stat/descriptive/AbstractStorelessUnivariateStatistic.html" title="class in org.apache.commons.math3.stat.descriptive">AbstractStorelessUnivariateStatistic</a></code></dd>
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<h4>evaluate</h4>
<pre>public&nbsp;double&nbsp;evaluate(double[]&nbsp;values)
                throws <a href="../../../../../../../org/apache/commons/math3/exception/MathIllegalArgumentException.html" title="class in org.apache.commons.math3.exception">MathIllegalArgumentException</a></pre>
<div class="block">Returns the variance of the entries in the input array, or
 <code>Double.NaN</code> if the array is empty.
 <p>
 See <a href="../../../../../../../org/apache/commons/math3/stat/descriptive/moment/Variance.html" title="class in org.apache.commons.math3.stat.descriptive.moment"><code>Variance</code></a> for details on the computing algorithm.</p>
 <p>
 Returns 0 for a single-value (i.e. length = 1) sample.</p>
 <p>
 Throws <code>MathIllegalArgumentException</code> if the array is null.</p>
 <p>
 Does not change the internal state of the statistic.</p></div>
<dl>
<dt><strong>Specified by:</strong></dt>
<dd><code><a href="../../../../../../../org/apache/commons/math3/stat/descriptive/UnivariateStatistic.html#evaluate(double[])">evaluate</a></code>&nbsp;in interface&nbsp;<code><a href="../../../../../../../org/apache/commons/math3/stat/descriptive/UnivariateStatistic.html" title="interface in org.apache.commons.math3.stat.descriptive">UnivariateStatistic</a></code></dd>
<dt><strong>Specified by:</strong></dt>
<dd><code><a href="../../../../../../../org/apache/commons/math3/util/MathArrays.Function.html#evaluate(double[])">evaluate</a></code>&nbsp;in interface&nbsp;<code><a href="../../../../../../../org/apache/commons/math3/util/MathArrays.Function.html" title="interface in org.apache.commons.math3.util">MathArrays.Function</a></code></dd>
<dt><strong>Overrides:</strong></dt>
<dd><code><a href="../../../../../../../org/apache/commons/math3/stat/descriptive/AbstractStorelessUnivariateStatistic.html#evaluate(double[])">evaluate</a></code>&nbsp;in class&nbsp;<code><a href="../../../../../../../org/apache/commons/math3/stat/descriptive/AbstractStorelessUnivariateStatistic.html" title="class in org.apache.commons.math3.stat.descriptive">AbstractStorelessUnivariateStatistic</a></code></dd>
<dt><span class="strong">Parameters:</span></dt><dd><code>values</code> - the input array</dd>
<dt><span class="strong">Returns:</span></dt><dd>the variance of the values or Double.NaN if length = 0</dd>
<dt><span class="strong">Throws:</span></dt>
<dd><code><a href="../../../../../../../org/apache/commons/math3/exception/MathIllegalArgumentException.html" title="class in org.apache.commons.math3.exception">MathIllegalArgumentException</a></code> - if the array is null</dd><dt><span class="strong">See Also:</span></dt><dd><a href="../../../../../../../org/apache/commons/math3/stat/descriptive/UnivariateStatistic.html#evaluate(double[])"><code>UnivariateStatistic.evaluate(double[])</code></a></dd></dl>
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<pre>public&nbsp;double&nbsp;evaluate(double[]&nbsp;values,
              int&nbsp;begin,
              int&nbsp;length)
                throws <a href="../../../../../../../org/apache/commons/math3/exception/MathIllegalArgumentException.html" title="class in org.apache.commons.math3.exception">MathIllegalArgumentException</a></pre>
<div class="block">Returns the variance of the entries in the specified portion of
 the input array, or <code>Double.NaN</code> if the designated subarray
 is empty.  Note that Double.NaN may also be returned if the input
 includes NaN and / or infinite values.
 <p>
 See <a href="../../../../../../../org/apache/commons/math3/stat/descriptive/moment/Variance.html" title="class in org.apache.commons.math3.stat.descriptive.moment"><code>Variance</code></a> for details on the computing algorithm.</p>
 <p>
 Returns 0 for a single-value (i.e. length = 1) sample.</p>
 <p>
 Does not change the internal state of the statistic.</p>
 <p>
 Throws <code>MathIllegalArgumentException</code> if the array is null.</p></div>
<dl>
<dt><strong>Specified by:</strong></dt>
<dd><code><a href="../../../../../../../org/apache/commons/math3/stat/descriptive/UnivariateStatistic.html#evaluate(double[],%20int,%20int)">evaluate</a></code>&nbsp;in interface&nbsp;<code><a href="../../../../../../../org/apache/commons/math3/stat/descriptive/UnivariateStatistic.html" title="interface in org.apache.commons.math3.stat.descriptive">UnivariateStatistic</a></code></dd>
<dt><strong>Specified by:</strong></dt>
<dd><code><a href="../../../../../../../org/apache/commons/math3/util/MathArrays.Function.html#evaluate(double[],%20int,%20int)">evaluate</a></code>&nbsp;in interface&nbsp;<code><a href="../../../../../../../org/apache/commons/math3/util/MathArrays.Function.html" title="interface in org.apache.commons.math3.util">MathArrays.Function</a></code></dd>
<dt><strong>Overrides:</strong></dt>
<dd><code><a href="../../../../../../../org/apache/commons/math3/stat/descriptive/AbstractStorelessUnivariateStatistic.html#evaluate(double[],%20int,%20int)">evaluate</a></code>&nbsp;in class&nbsp;<code><a href="../../../../../../../org/apache/commons/math3/stat/descriptive/AbstractStorelessUnivariateStatistic.html" title="class in org.apache.commons.math3.stat.descriptive">AbstractStorelessUnivariateStatistic</a></code></dd>
<dt><span class="strong">Parameters:</span></dt><dd><code>values</code> - the input array</dd><dd><code>begin</code> - index of the first array element to include</dd><dd><code>length</code> - the number of elements to include</dd>
<dt><span class="strong">Returns:</span></dt><dd>the variance of the values or Double.NaN if length = 0</dd>
<dt><span class="strong">Throws:</span></dt>
<dd><code><a href="../../../../../../../org/apache/commons/math3/exception/MathIllegalArgumentException.html" title="class in org.apache.commons.math3.exception">MathIllegalArgumentException</a></code> - if the array is null or the array index
  parameters are not valid</dd><dt><span class="strong">See Also:</span></dt><dd><a href="../../../../../../../org/apache/commons/math3/stat/descriptive/UnivariateStatistic.html#evaluate(double[],%20int,%20int)"><code>UnivariateStatistic.evaluate(double[], int, int)</code></a></dd></dl>
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<pre>public&nbsp;double&nbsp;evaluate(double[]&nbsp;values,
              double[]&nbsp;weights,
              int&nbsp;begin,
              int&nbsp;length)
                throws <a href="../../../../../../../org/apache/commons/math3/exception/MathIllegalArgumentException.html" title="class in org.apache.commons.math3.exception">MathIllegalArgumentException</a></pre>
<div class="block"><p>Returns the weighted variance of the entries in the specified portion of
 the input array, or <code>Double.NaN</code> if the designated subarray
 is empty.</p>
 <p>
 Uses the formula <pre>
   &Sigma;(weights[i]*(values[i] - weightedMean)<sup>2</sup>)/(&Sigma;(weights[i]) - 1)
 </pre>
 where weightedMean is the weighted mean</p>
 <p>
 This formula will not return the same result as the unweighted variance when all
 weights are equal, unless all weights are equal to 1. The formula assumes that
 weights are to be treated as "expansion values," as will be the case if for example
 the weights represent frequency counts. To normalize weights so that the denominator
 in the variance computation equals the length of the input vector minus one, use <pre>
   <code>evaluate(values, MathArrays.normalizeArray(weights, values.length)); </code>
 </pre>
 <p>
 Returns 0 for a single-value (i.e. length = 1) sample.</p>
 <p>
 Throws <code>IllegalArgumentException</code> if any of the following are true:
 <ul><li>the values array is null</li>
     <li>the weights array is null</li>
     <li>the weights array does not have the same length as the values array</li>
     <li>the weights array contains one or more infinite values</li>
     <li>the weights array contains one or more NaN values</li>
     <li>the weights array contains negative values</li>
     <li>the start and length arguments do not determine a valid array</li>
 </ul></p>
 <p>
 Does not change the internal state of the statistic.</p>
 <p>
 Throws <code>MathIllegalArgumentException</code> if either array is null.</p></div>
<dl>
<dt><strong>Specified by:</strong></dt>
<dd><code><a href="../../../../../../../org/apache/commons/math3/stat/descriptive/WeightedEvaluation.html#evaluate(double[],%20double[],%20int,%20int)">evaluate</a></code>&nbsp;in interface&nbsp;<code><a href="../../../../../../../org/apache/commons/math3/stat/descriptive/WeightedEvaluation.html" title="interface in org.apache.commons.math3.stat.descriptive">WeightedEvaluation</a></code></dd>
<dt><span class="strong">Parameters:</span></dt><dd><code>values</code> - the input array</dd><dd><code>weights</code> - the weights array</dd><dd><code>begin</code> - index of the first array element to include</dd><dd><code>length</code> - the number of elements to include</dd>
<dt><span class="strong">Returns:</span></dt><dd>the weighted variance of the values or Double.NaN if length = 0</dd>
<dt><span class="strong">Throws:</span></dt>
<dd><code><a href="../../../../../../../org/apache/commons/math3/exception/MathIllegalArgumentException.html" title="class in org.apache.commons.math3.exception">MathIllegalArgumentException</a></code> - if the parameters are not valid</dd><dt><span class="strong">Since:</span></dt>
  <dd>2.1</dd></dl>
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<h4>evaluate</h4>
<pre>public&nbsp;double&nbsp;evaluate(double[]&nbsp;values,
              double[]&nbsp;weights)
                throws <a href="../../../../../../../org/apache/commons/math3/exception/MathIllegalArgumentException.html" title="class in org.apache.commons.math3.exception">MathIllegalArgumentException</a></pre>
<div class="block"><p>
 Returns the weighted variance of the entries in the the input array.</p>
 <p>
 Uses the formula <pre>
   &Sigma;(weights[i]*(values[i] - weightedMean)<sup>2</sup>)/(&Sigma;(weights[i]) - 1)
 </pre>
 where weightedMean is the weighted mean</p>
 <p>
 This formula will not return the same result as the unweighted variance when all
 weights are equal, unless all weights are equal to 1. The formula assumes that
 weights are to be treated as "expansion values," as will be the case if for example
 the weights represent frequency counts. To normalize weights so that the denominator
 in the variance computation equals the length of the input vector minus one, use <pre>
   <code>evaluate(values, MathArrays.normalizeArray(weights, values.length)); </code>
 </pre>
 <p>
 Returns 0 for a single-value (i.e. length = 1) sample.</p>
 <p>
 Throws <code>MathIllegalArgumentException</code> if any of the following are true:
 <ul><li>the values array is null</li>
     <li>the weights array is null</li>
     <li>the weights array does not have the same length as the values array</li>
     <li>the weights array contains one or more infinite values</li>
     <li>the weights array contains one or more NaN values</li>
     <li>the weights array contains negative values</li>
 </ul></p>
 <p>
 Does not change the internal state of the statistic.</p>
 <p>
 Throws <code>MathIllegalArgumentException</code> if either array is null.</p></div>
<dl>
<dt><strong>Specified by:</strong></dt>
<dd><code><a href="../../../../../../../org/apache/commons/math3/stat/descriptive/WeightedEvaluation.html#evaluate(double[],%20double[])">evaluate</a></code>&nbsp;in interface&nbsp;<code><a href="../../../../../../../org/apache/commons/math3/stat/descriptive/WeightedEvaluation.html" title="interface in org.apache.commons.math3.stat.descriptive">WeightedEvaluation</a></code></dd>
<dt><span class="strong">Parameters:</span></dt><dd><code>values</code> - the input array</dd><dd><code>weights</code> - the weights array</dd>
<dt><span class="strong">Returns:</span></dt><dd>the weighted variance of the values</dd>
<dt><span class="strong">Throws:</span></dt>
<dd><code><a href="../../../../../../../org/apache/commons/math3/exception/MathIllegalArgumentException.html" title="class in org.apache.commons.math3.exception">MathIllegalArgumentException</a></code> - if the parameters are not valid</dd><dt><span class="strong">Since:</span></dt>
  <dd>2.1</dd></dl>
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<pre>public&nbsp;double&nbsp;evaluate(double[]&nbsp;values,
              double&nbsp;mean,
              int&nbsp;begin,
              int&nbsp;length)
                throws <a href="../../../../../../../org/apache/commons/math3/exception/MathIllegalArgumentException.html" title="class in org.apache.commons.math3.exception">MathIllegalArgumentException</a></pre>
<div class="block">Returns the variance of the entries in the specified portion of
 the input array, using the precomputed mean value.  Returns
 <code>Double.NaN</code> if the designated subarray is empty.
 <p>
 See <a href="../../../../../../../org/apache/commons/math3/stat/descriptive/moment/Variance.html" title="class in org.apache.commons.math3.stat.descriptive.moment"><code>Variance</code></a> for details on the computing algorithm.</p>
 <p>
 The formula used assumes that the supplied mean value is the arithmetic
 mean of the sample data, not a known population parameter.  This method
 is supplied only to save computation when the mean has already been
 computed.</p>
 <p>
 Returns 0 for a single-value (i.e. length = 1) sample.</p>
 <p>
 Throws <code>MathIllegalArgumentException</code> if the array is null.</p>
 <p>
 Does not change the internal state of the statistic.</p></div>
<dl><dt><span class="strong">Parameters:</span></dt><dd><code>values</code> - the input array</dd><dd><code>mean</code> - the precomputed mean value</dd><dd><code>begin</code> - index of the first array element to include</dd><dd><code>length</code> - the number of elements to include</dd>
<dt><span class="strong">Returns:</span></dt><dd>the variance of the values or Double.NaN if length = 0</dd>
<dt><span class="strong">Throws:</span></dt>
<dd><code><a href="../../../../../../../org/apache/commons/math3/exception/MathIllegalArgumentException.html" title="class in org.apache.commons.math3.exception">MathIllegalArgumentException</a></code> - if the array is null or the array index
  parameters are not valid</dd></dl>
</li>
</ul>
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<h4>evaluate</h4>
<pre>public&nbsp;double&nbsp;evaluate(double[]&nbsp;values,
              double&nbsp;mean)
                throws <a href="../../../../../../../org/apache/commons/math3/exception/MathIllegalArgumentException.html" title="class in org.apache.commons.math3.exception">MathIllegalArgumentException</a></pre>
<div class="block">Returns the variance of the entries in the input array, using the
 precomputed mean value.  Returns <code>Double.NaN</code> if the array
 is empty.
 <p>
 See <a href="../../../../../../../org/apache/commons/math3/stat/descriptive/moment/Variance.html" title="class in org.apache.commons.math3.stat.descriptive.moment"><code>Variance</code></a> for details on the computing algorithm.</p>
 <p>
 If <code>isBiasCorrected</code> is <code>true</code> the formula used
 assumes that the supplied mean value is the arithmetic mean of the
 sample data, not a known population parameter.  If the mean is a known
 population parameter, or if the "population" version of the variance is
 desired, set <code>isBiasCorrected</code> to <code>false</code> before
 invoking this method.</p>
 <p>
 Returns 0 for a single-value (i.e. length = 1) sample.</p>
 <p>
 Throws <code>MathIllegalArgumentException</code> if the array is null.</p>
 <p>
 Does not change the internal state of the statistic.</p></div>
<dl><dt><span class="strong">Parameters:</span></dt><dd><code>values</code> - the input array</dd><dd><code>mean</code> - the precomputed mean value</dd>
<dt><span class="strong">Returns:</span></dt><dd>the variance of the values or Double.NaN if the array is empty</dd>
<dt><span class="strong">Throws:</span></dt>
<dd><code><a href="../../../../../../../org/apache/commons/math3/exception/MathIllegalArgumentException.html" title="class in org.apache.commons.math3.exception">MathIllegalArgumentException</a></code> - if the array is null</dd></dl>
</li>
</ul>
<a name="evaluate(double[], double[], double, int, int)">
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<h4>evaluate</h4>
<pre>public&nbsp;double&nbsp;evaluate(double[]&nbsp;values,
              double[]&nbsp;weights,
              double&nbsp;mean,
              int&nbsp;begin,
              int&nbsp;length)
                throws <a href="../../../../../../../org/apache/commons/math3/exception/MathIllegalArgumentException.html" title="class in org.apache.commons.math3.exception">MathIllegalArgumentException</a></pre>
<div class="block">Returns the weighted variance of the entries in the specified portion of
 the input array, using the precomputed weighted mean value.  Returns
 <code>Double.NaN</code> if the designated subarray is empty.
 <p>
 Uses the formula <pre>
   &Sigma;(weights[i]*(values[i] - mean)<sup>2</sup>)/(&Sigma;(weights[i]) - 1)
 </pre></p>
 <p>
 The formula used assumes that the supplied mean value is the weighted arithmetic
 mean of the sample data, not a known population parameter. This method
 is supplied only to save computation when the mean has already been
 computed.</p>
 <p>
 This formula will not return the same result as the unweighted variance when all
 weights are equal, unless all weights are equal to 1. The formula assumes that
 weights are to be treated as "expansion values," as will be the case if for example
 the weights represent frequency counts. To normalize weights so that the denominator
 in the variance computation equals the length of the input vector minus one, use <pre>
   <code>evaluate(values, MathArrays.normalizeArray(weights, values.length), mean); </code>
 </pre>
 <p>
 Returns 0 for a single-value (i.e. length = 1) sample.</p>
 <p>
 Throws <code>MathIllegalArgumentException</code> if any of the following are true:
 <ul><li>the values array is null</li>
     <li>the weights array is null</li>
     <li>the weights array does not have the same length as the values array</li>
     <li>the weights array contains one or more infinite values</li>
     <li>the weights array contains one or more NaN values</li>
     <li>the weights array contains negative values</li>
     <li>the start and length arguments do not determine a valid array</li>
 </ul></p>
 <p>
 Does not change the internal state of the statistic.</p></div>
<dl><dt><span class="strong">Parameters:</span></dt><dd><code>values</code> - the input array</dd><dd><code>weights</code> - the weights array</dd><dd><code>mean</code> - the precomputed weighted mean value</dd><dd><code>begin</code> - index of the first array element to include</dd><dd><code>length</code> - the number of elements to include</dd>
<dt><span class="strong">Returns:</span></dt><dd>the variance of the values or Double.NaN if length = 0</dd>
<dt><span class="strong">Throws:</span></dt>
<dd><code><a href="../../../../../../../org/apache/commons/math3/exception/MathIllegalArgumentException.html" title="class in org.apache.commons.math3.exception">MathIllegalArgumentException</a></code> - if the parameters are not valid</dd><dt><span class="strong">Since:</span></dt>
  <dd>2.1</dd></dl>
</li>
</ul>
<a name="evaluate(double[], double[], double)">
<!--   -->
</a>
<ul class="blockList">
<li class="blockList">
<h4>evaluate</h4>
<pre>public&nbsp;double&nbsp;evaluate(double[]&nbsp;values,
              double[]&nbsp;weights,
              double&nbsp;mean)
                throws <a href="../../../../../../../org/apache/commons/math3/exception/MathIllegalArgumentException.html" title="class in org.apache.commons.math3.exception">MathIllegalArgumentException</a></pre>
<div class="block"><p>Returns the weighted variance of the values in the input array, using
 the precomputed weighted mean value.</p>
 <p>
 Uses the formula <pre>
   &Sigma;(weights[i]*(values[i] - mean)<sup>2</sup>)/(&Sigma;(weights[i]) - 1)
 </pre></p>
 <p>
 The formula used assumes that the supplied mean value is the weighted arithmetic
 mean of the sample data, not a known population parameter. This method
 is supplied only to save computation when the mean has already been
 computed.</p>
 <p>
 This formula will not return the same result as the unweighted variance when all
 weights are equal, unless all weights are equal to 1. The formula assumes that
 weights are to be treated as "expansion values," as will be the case if for example
 the weights represent frequency counts. To normalize weights so that the denominator
 in the variance computation equals the length of the input vector minus one, use <pre>
   <code>evaluate(values, MathArrays.normalizeArray(weights, values.length), mean); </code>
 </pre>
 <p>
 Returns 0 for a single-value (i.e. length = 1) sample.</p>
 <p>
 Throws <code>MathIllegalArgumentException</code> if any of the following are true:
 <ul><li>the values array is null</li>
     <li>the weights array is null</li>
     <li>the weights array does not have the same length as the values array</li>
     <li>the weights array contains one or more infinite values</li>
     <li>the weights array contains one or more NaN values</li>
     <li>the weights array contains negative values</li>
 </ul></p>
 <p>
 Does not change the internal state of the statistic.</p></div>
<dl><dt><span class="strong">Parameters:</span></dt><dd><code>values</code> - the input array</dd><dd><code>weights</code> - the weights array</dd><dd><code>mean</code> - the precomputed weighted mean value</dd>
<dt><span class="strong">Returns:</span></dt><dd>the variance of the values or Double.NaN if length = 0</dd>
<dt><span class="strong">Throws:</span></dt>
<dd><code><a href="../../../../../../../org/apache/commons/math3/exception/MathIllegalArgumentException.html" title="class in org.apache.commons.math3.exception">MathIllegalArgumentException</a></code> - if the parameters are not valid</dd><dt><span class="strong">Since:</span></dt>
  <dd>2.1</dd></dl>
</li>
</ul>
<a name="isBiasCorrected()">
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</a>
<ul class="blockList">
<li class="blockList">
<h4>isBiasCorrected</h4>
<pre>public&nbsp;boolean&nbsp;isBiasCorrected()</pre>
<dl><dt><span class="strong">Returns:</span></dt><dd>Returns the isBiasCorrected.</dd></dl>
</li>
</ul>
<a name="setBiasCorrected(boolean)">
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<h4>setBiasCorrected</h4>
<pre>public&nbsp;void&nbsp;setBiasCorrected(boolean&nbsp;biasCorrected)</pre>
<dl><dt><span class="strong">Parameters:</span></dt><dd><code>biasCorrected</code> - The isBiasCorrected to set.</dd></dl>
</li>
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<h4>copy</h4>
<pre>public&nbsp;<a href="../../../../../../../org/apache/commons/math3/stat/descriptive/moment/Variance.html" title="class in org.apache.commons.math3.stat.descriptive.moment">Variance</a>&nbsp;copy()</pre>
<div class="block">Returns a copy of the statistic with the same internal state.</div>
<dl>
<dt><strong>Specified by:</strong></dt>
<dd><code><a href="../../../../../../../org/apache/commons/math3/stat/descriptive/StorelessUnivariateStatistic.html#copy()">copy</a></code>&nbsp;in interface&nbsp;<code><a href="../../../../../../../org/apache/commons/math3/stat/descriptive/StorelessUnivariateStatistic.html" title="interface in org.apache.commons.math3.stat.descriptive">StorelessUnivariateStatistic</a></code></dd>
<dt><strong>Specified by:</strong></dt>
<dd><code><a href="../../../../../../../org/apache/commons/math3/stat/descriptive/UnivariateStatistic.html#copy()">copy</a></code>&nbsp;in interface&nbsp;<code><a href="../../../../../../../org/apache/commons/math3/stat/descriptive/UnivariateStatistic.html" title="interface in org.apache.commons.math3.stat.descriptive">UnivariateStatistic</a></code></dd>
<dt><strong>Specified by:</strong></dt>
<dd><code><a href="../../../../../../../org/apache/commons/math3/stat/descriptive/AbstractStorelessUnivariateStatistic.html#copy()">copy</a></code>&nbsp;in class&nbsp;<code><a href="../../../../../../../org/apache/commons/math3/stat/descriptive/AbstractStorelessUnivariateStatistic.html" title="class in org.apache.commons.math3.stat.descriptive">AbstractStorelessUnivariateStatistic</a></code></dd>
<dt><span class="strong">Returns:</span></dt><dd>a copy of the statistic</dd></dl>
</li>
</ul>
<a name="copy(org.apache.commons.math3.stat.descriptive.moment.Variance, org.apache.commons.math3.stat.descriptive.moment.Variance)">
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<h4>copy</h4>
<pre>public static&nbsp;void&nbsp;copy(<a href="../../../../../../../org/apache/commons/math3/stat/descriptive/moment/Variance.html" title="class in org.apache.commons.math3.stat.descriptive.moment">Variance</a>&nbsp;source,
        <a href="../../../../../../../org/apache/commons/math3/stat/descriptive/moment/Variance.html" title="class in org.apache.commons.math3.stat.descriptive.moment">Variance</a>&nbsp;dest)
                 throws <a href="../../../../../../../org/apache/commons/math3/exception/NullArgumentException.html" title="class in org.apache.commons.math3.exception">NullArgumentException</a></pre>
<div class="block">Copies source to dest.
 <p>Neither source nor dest can be null.</p></div>
<dl><dt><span class="strong">Parameters:</span></dt><dd><code>source</code> - Variance to copy</dd><dd><code>dest</code> - Variance to copy to</dd>
<dt><span class="strong">Throws:</span></dt>
<dd><code><a href="../../../../../../../org/apache/commons/math3/exception/NullArgumentException.html" title="class in org.apache.commons.math3.exception">NullArgumentException</a></code> - if either source or dest is null</dd></dl>
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